1. Technical Field
The embodiments herein generally relate to optical transport networks (OTN) and particularly relate to protecting work optical channel data unit (ODU) failures in the optical transport networks.
2. Description of the Related Art
Telecommunication networks are experiencing a massive increase in the demand for capacity, particularly in relation to internet traffic. To support this demand economically, optical networks are evolving which include a dynamically reconfigurable optical transport layer, based on fast optical cross-connects (OXCs) coupled with a suitable control and management architecture. In the near future it is expected that an optical transport network (OTN) will be realized capable of supporting large numbers of high capacity optical channels (OChs), with bit rates of 10-40 Gb/s.
OTN belongs to the class of TDM networks like SDH/SONET networks. In TDM networks an agreement between a transmit/upstream end and a receive/downstream end need to be done for time-slots of the client entities which are contained by a server entity. With respect to OTN, for setting up a lower order ODU (client) trail between the upstream end and the downstream end, the ends have to agree for the time-slots which the lower order ODU occupies inside the higher order ODU (server). With respect to a protection group comprising multiple work ODUs and a higher capacity protect ODU, a fundamental problem which arises when a work ODU needs to be protected using the protect ODU is the time-slots the protected work ODU occupies inside the higher capacity protect ODU. The upstream and downstream end need to know at the time of protection switching these time slots which the protected work ODU occupies inside the protect ODU. At present none of the existing protocols or the protection mechanisms provide any means for communicating these time-slots over the protection protocol in the TDM world. In case of all the existing protection schemes in the TDM world whether it be linear protection or ring protection scheme, for a work entity which gets protected the protect time-slot is always known before hand. Say for example, in linear scheme MSP the time-slot of AU/TU in the protect section layer is the same as what is on the work. Hence a relation between work and protect time-slot is fixed. This is due to the reason that the work and the protect-entities forming the protection group were of same capacity in the prior art. Hence, in prior art the case where the work entities and protect entities are of dissimilar capacities is not discussed.
In the existing techniques, no known protocols exists to exchange the time-slots of the protected work ODU inside the protect ODU, furthermore the structure and behavior of the protection controller and the signaling sequences are not known and deterministic behavior with respect to various failure cases like user initiated external commands, priority of the entities needs to be defined and the protection mechanism must handle all these cases. Based on the aforementioned, a higher capacity protect ODU cannot protect multiple lower capacity work ODUs on failure even though bandwidth is available in the protect ODU based on the prior art TDM protection schemes.
There exists a need for a method and system for protecting multiple lower capacity work ODU failures using a protect ODU of higher capacity in an optical transport network.
The abovementioned shortcomings, disadvantages and problems are addressed herein and which will be understood by reading and studying the following specification.